Microelectro-mechanical systems (MEMS) microphone package device and MEMS packaging method thereof

ABSTRACT

A MEMS microphone package device includes a MEMS microphone chip as an integrated circuit chip. An acoustic sensing structure is embedded in the integrated circuit chip. An adhesive structure adheres on outer sidewall of the microphone chip. A bottom portion of the adhesive structure protrudes out from first surface of the microphone chip and adheres on a surface of a substrate, having interconnection structure, to form a first seal ring. A space between the acoustic sensing structure and the substrate and sealed by the first seal ring forms a second chamber. A cover adheres to top portion of the adhesive structure, covering over the cavity on the second surface of the microphone chip. The top portion of the adhesive structure forms as a second seal ring. A space between the cover and the second surface of the microphone chip and sealed by the second seal ring forms a first chamber.

BACKGROUND

1. Field of Invention

The present invention relates to MEMS microphone package device and MEMS packaging method.

2. Description of Related Art

The Silicon MEMS microphone chip, such as MEMS microphone, has been proposed to form a microphone with rather reduced volume and then can be easily implemented into the large system.

FIG. 1 is a drawing, schematically illustrating a conventional MEMS microphone after packaging. In FIG. 1, a Silicon MEMS microphone chip 52 and an integrated circuit chip 56 are implemented on the substrate 50 with proper wire bonding. The substrate functions as a circuit board for communicating between the Silicon MEMS microphone chip 52 and the integrated circuit chip 56. The Silicon MEMS microphone chip 52 can sense an acoustic source received from an acoustic aperture 62 of a cap 58 and convert the acoustic source into electric signal. In order to process the sensing signal, the integrated circuit chip 56 receives the sensing signal through the substrate 50 for subsequent processing. The Silicon MEMS microphone chip 52 has a chamber 54, serving as a back chamber. The cap 58 disposed over the substrate 50 can form a chamber 60, serving as a front chamber with sufficient volume, so that an acoustic sensing structure of the Silicon MEMS microphone chip 52 having a diaphragm structure can vibrate or sense with the acoustic source.

Due to different designs of the Silicon MEMS microphone chip 52, the Silicon MEMS microphone chip 52 may sense the acoustic source from the other side. In this situation, the acoustic aperture 62 in FIG. 1 may be changed to the substrate 50. FIG. 2 is a drawing, schematically illustrating a conventional MEMS microphone after packaging. In FIG. 2, the Silicon MEMS microphone chip 52 is designed to receive the acoustic source from the side, which is attached to the substrate 50. Then, the acoustic aperture 62 is formed in the substrate 50. In this type of Silicon MEMS microphone chip, the chamber 54 now is serving as a front chamber, and the chamber 60 is serving as a back chamber. The front chamber receives the acoustic source.

For the conventional MEMS microphone, it needs the Silicon MEMS microphone chip 52 and the integrated circuit chip 56 as two chips. Further the package size is relatively large.

SUMMARY OF THE INVENTION

The invention provides a MEMS microphone package device and the MEMS packaging method, the package structure can at least be in smaller volume and be a single chip.

In an embodiment, a MEMS microphone package structure includes a silicon MEMS microphone chip, a substrate, an adhesive structure, and a cover. The silicon MEMS microphone chip is an integrated circuit chip and an acoustic sensing structure, embedded in the integrated circuit chip. The silicon MEMS microphone chip has a first surface and a second surface. An integrated circuit and one side of an acoustic sensing structure of the silicon MEMS microphone chip are exposed at the first surface. Acoustic signals are received by the acoustic sensing structure and transferred to electrical signals via the integrated circuit. The cavity is formed at the second surface of the silicon MEMS microphone chip to expose the other side of the acoustic sensing structure on the second surface of the silicon MEMS microphone chip. The substrate has an interconnection structure in the substrate. The adhesive structure adheres on an outer sidewall of the silicon MEMS microphone chip. A bottom portion of the adhesive structure protrudes out from the first surface of the silicon MEMS microphone chip and adheres on a surface of the substrate to form a first seal ring. A space between the acoustic sensing structure and the substrate and sealed by the first seal ring forms a second chamber. A cover adheres to a top portion of the adhesive structure, covering over the cavity on the second surface of the silicon MEMS microphone chip. The top portion of the adhesive structure forms as a second seal ring, wherein a space between the cover and the second surface of the silicon MEMS microphone chip and sealed by the second seal ring forms a first chamber. The cavity is connected to the first chamber acoustically.

In an embodiment, a MEMS packaging method comprises: providing a substrate, having a first surface and a second surface, wherein the substrate has been predetermined with a plurality packaging units, an interconnection structure is formed in the substrate corresponding each of the packaging units, wherein the interconnection structure has a plurality of first connecting pads on the first surface and a plurality of second connection pads on the second surface; adhering a plurality of silicon MEMS microphone chips to the packaging units on the first connecting pads by conductive adhesive material on the first connection pads; forming an adhesive structure, adhering on an outer sidewall of each of the silicon MEMS microphone chips, wherein a bottom portion of the adhesive structure in each of the silicon MEMS microphone chips protrudes out from a bottom of the silicon MEMS microphone chips and adheres on the first surface of the substrate to form a first seal ring in close form, and a top portion of the adhesive structure in each of the silicon MEMS microphone chips protrudes out from a top of the silicon MEMS microphone chips; forming a plurality of covers; adhering the covers respectively to the silicon MEMS microphone chips on the top portion of the adhesive structure, wherein a second seal ring in close form corresponding to each of the silicon MEMS microphone chips is formed; and singulating the packaging units into a plurality of single-device chips.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a drawing, schematically illustrating a conventional MEMS microphone after packaging.

FIG. 2 is a drawing, schematically illustrating another conventional MEMS microphone after packaging.

FIG. 3 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention.

FIG. 4 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention.

FIG. 5A is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention.

FIG. 5B is a drawing, schematically a top view of the Silicon MEMS microphone chip of the MEMS microphone package device in FIG. 5A, according to an embodiment of the invention.

FIGS. 6A-6B are drawings, schematically cross-section views MEMS microphone package devices, according to an embodiment of the invention.

FIG. 7 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention.

FIGS. 8A-8E are drawings, schematically illustrating the fabrication flow for packaging a MEMS microphone package device with cross-sectional views, according to an embodiment of the invention.

FIGS. 9A-9E are drawings, schematically illustrating the fabrication flow for packaging a MEMS microphone package device with cross-sectional views, according to an embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the invention, the Silicon MEMS microphone chip has the integrated circuit embedded in the same chip. The Silicon MEMS microphone chip in package is a single ship. The Silicon MEMS microphone chip can be adhered to the substrate by the adhesive structure for form a fully sealed space except the acoustic aperture to receive the acoustic source from the environment.

Several embodiments are provided for descriptions of the invention. However, the invention is not just limited to the provided embodiments.

FIG. 3 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention. In FIG. 3, a MEMS microphone package device 120 includes a substrate 100 as a base. The substrate 100 has interconnection structure 104, which has multiple connection pads 104, such as metal pad, on both surfaces of the substrate. In FIG. 3, only one connection pad is shown. However, it can be understood that the interconnection structure generally is the circuit path communication between the integrated circuit 110 and the acoustic sensing structure 108, which functions as a transducer. The substrate 100 in this embodiment may also have an indent space 102 to serving as a main part of a chamber. The chamber can be further referred as a back chamber because the Silicon MEMS microphone chip 106 is a type to sense the acoustic signal from a front side, opposite to the back chamber or the indent space 102. Here, the front chamber is usually called just because of on the location side of the acoustic aperture 118, which is connected to the front chamber to receive the acoustic source.

The Silicon MEMS microphone chip 106 includes a peripheral dielectric structure having a cavity 112. An acoustic sensing structure 108 within the cavity 112 is included and held by the peripheral dielectric structure to define a first chamber out from the cavity 112. The acoustic sensing structure 108 includes a diaphragm, which can sense the acoustic source received from the cover 116. The first chamber in this embodiment is serving as a front chamber. An integrated circuit 110 is also embedded in the peripheral dielectric structure of the Silicon MEMS microphone chip 106. The integrated circuit 110 further converts the acoustic signals sensed by the Silicon MEMS microphone chip 106 to the electric signals.

In addition, an adhesive structure 114 adheres on an outer sidewall of the Silicon MEMS microphone chip 106, wherein a bottom portion of the adhesive structure 114 protrudes out from a bottom, also referred as a first surface of the Silicon MEMS microphone chip 106 and adheres on a surface of the substrate 100 to form a first seal ring in close form, surrounding the cavity 112, which serves as a part of the first chamber or the front chamber in this embodiment as previously stated. However, a space between the acoustic sensing structure 108 and the substrate 110 and sealed by the first seal ring forms a second chamber, which includes the indent space 102 in the substrate. The second chamber is also referred as the back chamber in this embodiment because the front chamber receives the acoustic source from the acoustic aperture 118 in the cover 116. In this embodiment the cover 116 can be a flat plate as an example but the flat plate is not the only choice. The cover 116 adhered onto the top portion of the adhesive structure, which functions as a second seal ring in close form, surrounding the indent space 102. Here, since the top portion is protruding out from the top, also referred as a second surface, of the Silicon MEMS microphone chip 106, the addition space between the Silicon MEMS microphone chip 106 and the cover 116 is combined with the cavity 112 and also serves as a part of the front chamber.

Practically, a space between the cover 116 and the second surface of the silicon MEMS microphone chip 106 and sealed by the second seal ring forms the chamber. The cavity 112 as a part of the first chamber is connected to the first chamber acoustically. The space between the acoustic sensing structure 108 and the substrate 100 and sealed by the first seal ring forms the second chamber.

FIG. 4 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention. In FIG. 4, two or more MEMS microphone package device 120 with the same defined structure can be formed together as an array, such microphone array. In this situation, an addition interconnection structure 122 as a part of the interconnection 104 can be further included to communicate to one another.

FIG. 5A is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention. In FIG. 5A, the acoustic aperture 118 is used to receive the acoustic source from the environment. However, the air in the environment may have micro particles as the dust, which may also enter into the front chamber. The particles may fall and stick to the acoustic sensing structure 108, causing a reduction or even a stop of the vibration of the diaphragm included inside. The sensitivity of the acoustic sensing structure 108 would fail in function. Usually, the acoustic aperture 118 may be formed above the cavity 112 is alignment without consider the effect from the dust. However, when considering the effect caused by the dust, the acoustic aperture 118 is shifted from the cavity 112, so when the micro particles of the dust enter the front chamber, a significant portion of the micro particles may fall onto the peripheral dielectric structure of the Silicon MEMS microphone chip 106 without falling onto the acoustic sensing structure 108.

In further consideration, since the gap between the cover 116 and the top of Silicon MEMS microphone chip 106 may be not sufficient to guide the acoustic source into the cavity 112 and reaching to the acoustic sensing structure 108, an acoustic channel 130 can be further formed in the peripheral dielectric structure of the Silicon MEMS microphone chip 106.

FIG. 5B is a drawing, schematically a top view of the Silicon MEMS microphone chip of the MEMS microphone package device in FIG. 5A, according to an embodiment of the invention. Also referring to FIG. 5B with FIG. 5A, the cavity 112 in the Silicon MEMS microphone chip 106 has a round periphery in this example. The acoustic channel 130 can be a trench, so that the acoustic channel 130 can more efficiently guide the acoustic source into the cavity 112. However, the micro particles may fall on the bottom of the acoustic channel 130 without entering to the cavity 112.

FIGS. 6A-6B are drawings, schematically cross-section views MEMS microphone package devices, according to an embodiment of the invention. In FIG. 6A, another MEMS microphone package device 250 is disclosed, which includes the Silicon MEMS microphone chip 206 designed to receive acoustic source from the different side with respect to the Silicon MEMS microphone chip 106 in FIG. 3. In this example, the Silicon MEMS microphone chip 206 also has the acoustic sensing structure 208 and the integrated circuit 210 embedded in the Silicon MEMS microphone chip 206. The substrate 200 also has the interconnection structure 204 with the connection pads on both surfaces thereof. The adhesive structure 212, like the adhesive structure 114, is formed fully on the sidewall of the Silicon MEMS microphone chip 206 with the protruding bottom portion and the protruding top portion.

The bottom portion of the adhesive structure 212 adheres onto the substrate 200 and then a front chamber 203 is formed between the substrate 200 and the Silicon MEMS microphone chip 206. The acoustic aperture is formed in the substrate 200 in this example. Like the descriptions in FIG. 5A and FIG. 5B about the location of the acoustic aperture 118, the location of the acoustic aperture 202 can be aligned to or shifted from the cavity 216 of the Silicon MEMS microphone chip 206. The acoustic channel 130 may also addition made.

The cover 214 in this example is to form a back chamber, which has combined the cavity 216 of the Silicon MEMS microphone chip 206. In order to add more space to allow the diaphragm to vibrate with sufficient amplitude under the desired sensitivity, the cover 214 can be a cap-like structure. However, the cap-like structure is not the only choice.

In FIG. 6B, it is basically the same as the one in FIG. 6A but the substrate have additional indent structure to form the front chamber 203′. The other details can be referred to FIG. 6A and are not repeated in description.

FIG. 7 is a drawing, schematically a cross-section view of a MEMS microphone package device, according to an embodiment of the invention. In FIG. 7, bases on the MEMS microphone package device 250, multiple MEMS microphone package devices 250 like the manner in FIG. 4 can be formed together as an array. The addition interconnection structure 252 as a part of the interconnection structure 204 can be included for communication one another.

FIGS. 8A-8E are drawings, schematically illustrating the fabrication follow for packaging a MEMS microphone package device with cross-sectional views, according to an embodiment of the invention. The MEMS packaging method for the MEMS microphone package device 120 are now described. In FIG. 8A, a substrate 100 is provided. The substrate has a first surface and a second surface and the substrate 100 has been predetermined with a plurality packaging units. An interconnection structure 104 is formed in the substrate 100 corresponding each of the packaging units. The interconnection structure 104 has a plurality of first connecting pads on the first surface and a plurality of second connection pads on the second surface. A conductive adhesive material 105 may be formed on the connection pads at the first surface. The substrate also has the indent space 102 corresponding to each Silicon MEMS microphone chip, which is disposed later.

Remarkably, in considering the array as described in FIG. 4 and FIG. 7, each of the packaging units is configured to adapt at least one of the Silicon MEMS microphone chips. If two or more of the Silicon MEMS microphone chips are configured, the multiple Silicon MEMS microphone chips communicate to one another by an additional portion of the interconnection structure in the substrate.

In FIG. 8B, a plurality of Silicon MEMS microphone chips 106 are respectively adhered to the packaging units on the first connecting pads by conductive adhesive material 105 on the first connection pads. Here, one Silicon MEMS microphone chip 106 usually has multiple connection pads. However, the number of the connection pads shown in the cross-sectional view of the example is one. This FIG. 8B does not limits the number of the connection pads. The interconnection structure 104 is connected to the integrated circuit embedded in the Silicon MEMS microphone chip 106, as previous described in package structure. Further, connection bump 101 may also pre-formed on the connection pads at the second surface of the substrate 100 for later electrical connection to external circuit system.

In FIG. 8C, the adhesive structure is formed adhering on an outer sidewall of each of the Silicon MEMS microphone chips 106, wherein a bottom portion of the adhesive structure in each of the Silicon MEMS microphone chips 106 protrudes out from a bottom of the Silicon MEMS microphone chips 106 and adheres on the first surface of the substrate 100 to form a first seal ring in close form. A top portion of the adhesive structure 114 in each of the Silicon MEMS microphone chips 106 protrudes out from a top of the Silicon MEMS microphone chips 106.

In FIG. 8D, multiple covers 116 are formed. Then, the covers 116 are adhered respectively to the Silicon MEMS microphone chips 106 on the top portion of the adhesive structure 114. Due to the top portion of the adhesive structure 114, a second seal ring in close form corresponding to each of the Silicon MEMS microphone chips is then formed. In FIG. 8E, the packaging units are singulated into a plurality of individual ones of single-device chips by a singulating process 140.

As can be seen in this example, the MEMS microphone package device is taking the example from FIG. 3, so the cover 116 has the acoustic aperture.

FIGS. 9A-9E are drawings, schematically illustrating the fabrication follow for packaging a MEMS microphone package device with cross-sectional views, according to an embodiment of the invention. If the MEMS microphone package device is taking from FIG. 6B as an example, the package processes are described. The general aspect in FIGS. 9A-9E is similar to the aspect in FIG. 8A-8E. The further remarkable notes are described as follows.

In FIG. 9A, the substrate 200 is provided. The substrate 200 is also configured into multiple packaging units. Here in this example, one packaging unit is corresponding to one MEMS microphone package device 250 shown in FIG. 6B. Alternatively, one packaging unit can include multiple MEMS microphone package devices 250 in an array as stated in FIG. 7. However, each Silicon MEMS microphone chip is packaged in the manner. In this example, the acoustic aperture 202 in the substrate 200 has been formed, corresponding to one Silicon MEMS microphone chip. In addition, the conductive adhesive material 205 can be formed on the connection pads. An indent structure 206′ is also formed on the substrate 200.

In FIG. 9B, multiple Silicon MEMS microphone chip 206 are adhered to the substrate 200 on connection pads by the conductive adhesive material 205. Further, the connection bump 201 may also pre-formed on the connection pads at the second surface of the substrate 200. In FIG. 9C, the adhesive structure 212 are formed on each Silicon MEMS microphone chip 206 at the full outer sidewall.

In FIG. 9D, multiple covers 214 are respectively adhered to the top portion of the adhesive structures on the Silicon MEMS microphone chips 206. In this example, the cover 214 can be a cap-like structure without acoustic aperture. In FIG. 9E, after the package structure units are completed, the singulating process 240 is performed to cut the package structure units into individuals.

It can be noted that the Silicon MEMS microphone chip has included the embedded integrated circuit. The substrate includes the interconnection structure, so that connection terminals, such as I/O terminals, of the silicon MEMS microphone chip with the integrated circuit can be extended to the connection pads on the substrate. The adhesive structure adheres the silicon MEMS microphone chip and the substrate into a single chip by a reduced volume. Further as to the packaging method in FIGS. 8A-8E and FIGS. 9A-9E, the packaging processes are basically the same except the acoustic aperture corresponding to the type of the Silicon MEMS microphone chip.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents. 

What is claimed is:
 1. A micro-electromechanical systems (MEMS) microphone package device, comprising: a silicon MEMS microphone chip, wherein the silicon MEMS microphone chip is an integrated circuit chip and an acoustic sensing structure embedded in the integrated circuit chip, wherein the silicon MEMS microphone chip has a first surface and a second surface, wherein an integrated circuit and one side of an acoustic sensing structure of the silicon MEMS microphone chip are exposed at the first surface, wherein acoustic signals are received by the acoustic sensing structure and transferred to electrical signals via the integrated circuit, wherein a cavity is formed at the second surface of the silicon MEMS microphone chip to expose the other side of the acoustic sensing structure on the second surface of the silicon MEMS microphone chip; a substrate, having an interconnection structure in the substrate; an adhesive structure, adhering on an outer sidewall of the silicon MEMS microphone chip, wherein a bottom portion of the adhesive structure protrudes out from the first surface of the silicon MEMS microphone chip and adheres on a surface of the substrate to form a first seal ring, wherein a space between the acoustic sensing structure and the substrate and sealed by the first seal ring forms a second chamber; and a cover, adhering to a top portion of the adhesive structure, covering over the cavity on the second surface of the silicon MEMS microphone chip, wherein the top portion of the adhesive structure forms as a second seal ring, wherein a space between the cover and the second surface of the silicon MEMS microphone chip and sealed by the second seal ring forms a first chamber, wherein the cavity is connected to the first chamber acoustically.
 2. The MEMS microphone package device of claim 1, wherein the silicon MEMS microphone chip servers as a first MEMS microphone package unit as a single unit, or the MEMS microphone package device further comprises at least one second MEMS microphone package unit with a same structure defined in the first MEMS microphone package unit, wherein the two MEMS microphone package units communicate to each other by an additional portion of the interconnection structure in the substrate.
 3. The MEMS microphone package device of claim 2, wherein the cover has an acoustic aperture to receive an acoustic source, and the acoustic aperture is at a location aligned to or shifted from the cavity of the silicon MEMS microphone chip.
 4. The MEMS microphone package device of claim 3, wherein the acoustic aperture is at the location shifted from the cavity in silicon MEMS microphone chip, and the silicon MEMS microphone chip has an acoustic channel for guiding the acoustic source received from the acoustic aperture to the cavity.
 5. The MEMS microphone package device of claim 3, wherein the substrate has an indent space under the acoustic sensing structure in silicon MEMS microphone chip to serve as a part of the second chamber for increasing volume.
 6. The MEMS microphone package device of claim 3, wherein the interconnection structure in the substrate is electrically connecting to the integrated circuit embedded in the silicon MEMS microphone chip.
 7. The MEMS microphone package device of claim 6, wherein the interconnection structure also includes at least one connection pad on a surface of the substrate, exposed to an environment for external connection.
 8. The MEMS microphone package device of claim 3, wherein the cover is a cap-like structure so as to increase a volume of first chamber, and the substrate has an acoustic aperture to receive an acoustic source into the second chamber, and the acoustic aperture is at a location aligned to or shifted from the acoustic sensing structure of the silicon MEMS microphone chip.
 9. The MEMS microphone package device of claim 8, wherein the substrate has an indent space under the acoustic sensing structure to serve as a part of the second chamber for increasing volume.
 10. The MEMS microphone package device of claim 8, wherein the interconnection structure in the substrate is electrically connecting to the integrated circuit embedded in the silicon MEMS microphone chip.
 11. The MEMS microphone package device of claim 10, wherein the interconnection structure also includes at least one connection pad on a surface of the substrate, exposed to an environment for external connection.
 12. A micro-electromechanical systems (MEMS) microphone packaging method, comprising: providing a substrate, having a first surface and a second surface, wherein the substrate has been predetermined with a plurality packaging units, an interconnection structure is formed in the substrate corresponding each of the packaging units, wherein the interconnection structure has a plurality of first connecting pads on the first surface and a plurality of second connection pads on the second surface; adhering a plurality of silicon MEMS microphone chips to the packaging units on the first connecting pads by conductive adhesive material on the first connection pads; forming an adhesive structure, adhering on an outer sidewall of each of the silicon MEMS microphone chips, wherein a bottom portion of the adhesive structure in each of the silicon MEMS microphone chips protrudes out from a bottom of the silicon MEMS microphone chips and adheres on the first surface of the substrate to form a first seal ring in close form, and a top portion of the adhesive structure in each of the silicon MEMS microphone chips protrudes out from a top of the silicon MEMS microphone chips; forming a plurality of covers; adhering the covers respectively to the silicon MEMS microphone chips on the top portion of the adhesive structure, wherein a second seal ring in close form corresponding to each of the silicon MEMS microphone chips is formed; and singulating the packaging units into a plurality of single-device chips.
 13. The MEMS microphone packaging method of claim 12, wherein each of the packaging units is configured to adapt at least one of the silicon MEMS microphone chips, wherein if two or more of the silicon MEMS microphone chips are configured, the multiple silicon MEMS microphone chips communicate to one another by an additional portion of the interconnection structure in the substrate.
 14. The MEMS microphone packaging method of claim 13, wherein the step of forming the covers comprises forming an acoustic aperture in each of the covers to receive an acoustic source, and the acoustic aperture is at a location aligned to or shifted from an cavity in each of the silicon MEMS microphone chips, the cavity is coupled to the acoustic sensing structure.
 15. The MEMS microphone packaging method of claim 14, wherein the acoustic aperture is at the location shifted from the cavity in each of the silicon MEMS microphone chips, and each of the silicon MEMS microphone chips has an acoustic channel for guiding the acoustic source received from the acoustic aperture to the cavity.
 16. The MEMS microphone packaging method of claim 13, wherein the substrate also has an indent space within each of the first seal rings.
 17. The MEMS microphone packaging method of claim 13, wherein the interconnection structure in the substrate is electrically connecting to an integrated circuit embedded in each of the silicon MEMS microphone chips.
 18. The MEMS microphone packaging method of claim 13, wherein the second connecting pads are exposed to an environment for external connection.
 19. The MEMS microphone packaging method of claim 13, wherein the cover formed in the step of forming the covers is a cap-like structure, and the substrate has an acoustic aperture corresponding to each of the silicon MEMS microphone chip to receive an acoustic source, wherein the acoustic aperture is at a location aligned to or shifted from a cavity of each of the silicon MEMS microphone chips, and the cavity is connected to an acoustic sensing structure acoustically.
 20. The MEMS microphone packaging method of claim 19, wherein the substrate further has an indent space within each of the first seal rings.
 21. The MEMS microphone packaging method of claim 19, wherein the interconnection structure in the substrate for each of the silicon MEMS microphone chip s is electrically connecting to an integrated circuit embedded in each of the silicon MEMS microphone chips. 